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How do ionization energy and electronegativity change down the carbon group?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — carbon group element Modern version of the periodic table of the elements (printable).

Within the carbon group, both ionization energy and electronegativity generally decrease as the atomic number increases.1

These trends are primarily consequences of the increase in atomic size down the group. As the atoms become larger, the valence electrons are located further from the nucleus and are shielded by intervening electronic shells. This increased distance and screening result in a weaker attraction between the nucleus and the valence electrons, making it easier to remove an electron—thereby lowering the ionization energy—and reducing the atom's ability to attract electrons, which corresponds to a decrease in electronegativity.12

While these properties follow a general downward trend, it is important to note that the specific values for these elements can be influenced by the details of their electronic configurations and the presence of underlying electron arrangements.123